This invention relates to expression of a fused protein, more specifically to a fused DNA sequence including a DNA sequence coding a heat-resistant protein, a fused protein expressed by said fused DNA sequence, and a method for expressing said fused protein.
Progress in genetic engineering has enabled analysis of a protein which has been purified from a natural substance, at a genetic level and artificial amplification of a desired protein (Itakura et al., Science, vol. 198, p. 1056 (1977)). By application of a DNA sequence to which thioredoxin (hereinafter referred to as “TRX” in the specification) (International Provisional Patent Publication No. 507209/1993) or glutathione-S-transferase (hereinafter referred to as “GST” in the specification) (International Provisional Patent Publication No. 503441/1989) which has been invented thereafter is fused, even a protein which is inherently expressed with difficulty can be expressed, and a technique of expressing a fused protein has been used widely.
TRX and GST can be applied to fusion and expression of various proteins which are expressed with difficulty, but even in GST which has been essentially used for the purpose of expressing a soluble fused protein, a fused protein becomes insoluble depending on a protein to be fused so that productivity is lowered, or a fused protein to which TRX is fused may have a problem that a nonspecific reaction is liable to occur. Therefore, it has been desired to provide a fused protein having further excellent operatability and productivity.